Unexamined Japanese Patent Application Kokai Publication No. 2012-255770 (refer to Patent Literature 1) discloses a magnetic sensor device including a magnet and a magnetic resistance effect element (MR element). The magnet generates a cross magnetic field crossing the object-to-be-detected. In addition, the magnetic resistance effect element is disposed between the magnet and the object-to-be-detected, has an output terminal, and outputs a change in a conveying direction component of the cross magnetic field. This change in the resistance value is caused by the magnetic component of the object-to-be-detected conveyed in the cross magnetic field as a change in the resistance value. Patent Literature 1 describes, as a configuration configured to generate a cross magnetic field, a configuration in which magnets are arranged facing across each other the object-to-be-detected, and a configuration in which a magnet is placed on one side of the object-to-be-detected and magnetic material is placed facing across each other on the other surface of the object-to-be-detected.